Nigersaurus taqueti, a sauropod that lived in the Sahara region 110 million years ago, had a mouthful of slender teeth—more than 500 of them—packed inside its jaws. Each tooth was about the size of a toddler's incisor.

In a new study in the journal PLoS ONE, researchers used a CT scan on a skull to expose up to nine replacements stacked up behind each working tooth.

The teeth, coupled with its broad, flat jaw, allowed the dinosaur to constantly munch on ground vegetation—not much different from a cow.